1) PETE—Polyethylene terephthalate ethylene; drink, cleaner/detergent, and peanut butter containers.
2) HDPE—High Density Polyethylene; opaque milk/water jugs, bleach, detergent and shampoo bottles, some plastic bags, heavy duty bins and containers.
3) PVC or V—Polyvinyl Chloride or Vinyl; cling wrap, squeeze and cooking oil bottles, peanut butter jars, detergent and window cleaner bottles.
4) LDPE—Low Density Polyethylene; grocery bags, plastic wraps, some bottles, regular plastic bins and containers.
5) PP—Polypropylene; Rubbermaid, deli soup, syrup and yogurt containers, straws, other clouded plastic containers, baby bottles, ropes.
6) PS—Polystyrene; Styrofoams and plastic utensils.
7 ) Other—Typically polycarbonates; 5-gallon water bottles, “sport” water bottles, can liners, clear “sippy” cups , clear plastic cutlery. bio-based plastics. Bisphenol A (BPA) is a chemical building block that is used primarily to make polycarbonate plastic.
In addition to these seven groups, acrylic (polymethyl methacrylate) is another plastic of interest to aquarists.
There seems to be a consensus that types 1 through 5 are aquarium safe, though polycarbonate water jugs are also commonly used in saltwater applications. PETE is widely considered to be very safe for use in aquarium systems, even though it is known to leach the toxic metal antimony. HDPE is also considered to be safe, and is used in heavy duty containers such as trash bins. Such bins are often used as water storage containers. HDPE is simply a denser form of LDPE, which is also considered safe. Both are highly chemically resistant. PVC is probably one of the most ubiquitous plastics found in aquarium systems, as it is a common material used for plumbing water lines.
This having been said we really don't know yet. Many will advise letting the plastic sit around till it no longer smells.
